Originally, the huge shoulder blade and vertebra were thought to be from the same gigantic animal. It was estimated to be about 82-100+ feet long (25-30 m), about 50 feet (15 m) high, weighing 55 to 130 tons.

DISCOVERY AND NAMING OF ULTRASAUROS
Just a few bones of "Ultrasauros" were found in the Upper Jurassic Morrison Formation in western Colorado, USA, in 1979, by US paleontologist James A. Jensen (who also discovered Supersaurus in 1972). Jensen named it Ultrasaurus in 1985 (meaning "Ultra lizard"). It was renamed "Ultrasauros machintoshi" because there was already another dinosaur named Ultrasaurus (a smaller, early Cretaceous sauropod found in South Korea and named by Haang Mook Kim in 1983).

FOSSILS OF ULTRASAUROS
Only a shoulder blade (scapula), some vertebrae, and a partial hip have been found. These fossils are probably bits of a huge Brachiosaurus (the enormous shoulder bone) and a Supersaurus (the vertebrae).

CLASSIFICATION
Ultrasauros was a late-Jurassic Saurischian dinosaur (the order of lizard-hipped dinosaurs). It was a sauropodomorph (the large, plant eating dinosaurs) and a sauropod (very large herbivore). It's fossils are likely from Brachiosaurus and Supersaurus. The type species is U. machintoshi (Olshevsky, 1991). (Jensen originally called it Ultrasaurus, but another dinosaur from Korea had already been named Ultrasaurus, so the name had to be changed).

HABITAT
Ultrasauros (Brachiosaurus-Supersaurus) was a terrestrial animal. It was assumed for many years that giant sauropods spent most of their time in water, letting the water support their weighty bodies while breathing through their lofty nostrils. Now it is believed that they were fully terrestrial, just as Elmer S. Riggs, who first described Brachiosaurus, argued in a 1904 article. He believed, as most modern scientists do, that Brachiosaurus' feet and limbs were not broad enough to support the heavy animal in mud, that its back was flexible enough to support it on land, and that its chest was narrow and deep, which is insufficient for breathing underwater, and inconsistent with modern-day water-dwelling large animals (like hippos).

BEHAVIOR
Ultrasauros (Brachiosaurus-Supersaurus), like other sauropods, may have travelled in herds and may have migrated when they depleted their local food supply. Ultrasauros may have hatched from eggs, like other sauropods. Sauropod eggs have been found in a linear pattern and not in nests; presumably the eggs were laid as the animal was walking. It is thought that sauropods did not take care of their eggs. Sauropods life spans may have been in the order of 100 years.

INTELLIGENCE
It used to be thought that the sauropods (like Ultrasauros, Brachiosaurus and Supersaurus) had a second brain. Paleontologists now think that what they thought was a second brain was just an enlargement in the spinal cord in the hip area. This enlargement was larger than the animal's tiny brain.

Ultrasauros (Brachiosaurus-Supersaurus) was a sauropod, whose intelligence (as measured by its relative brain to body weight, or EQ) was the among the lowest of the dinosaurs.

LOCOMOTION
Ultrasauros (Brachiosaurus-Supersaurus) walked slowly on four long legs.

PRINTOUTS/ACTIVITIES
Ultrasauros printout

K-3 Ultrasauros printout to color

Ultrasauros bried fact sheet or a printable version.